U.S. patent number 4,271,784 [Application Number 06/071,022] was granted by the patent office on 1981-06-09 for apparatus for discharging a fatigued developing agent in a magnetic brush developing device.
This patent grant is currently assigned to Olympus Optical Co., Ltd.. Invention is credited to Osamu Ishimoto, Kiyoshi Miyashita, Hiroshi Tsuda.
United States Patent |
4,271,784 |
Ishimoto , et al. |
June 9, 1981 |
**Please see images for:
( Certificate of Correction ) ** |
Apparatus for discharging a fatigued developing agent in a magnetic
brush developing device
Abstract
An apparatus for discharging a used and fatigued developing
agent from a magnetic brush developing device installed in a main
body of a copying machine, which developing device has a housing
with an opening at a position which is opposed to a charge
retentive member such as a photosensitive drum and a record paper,
a sleeve made of non-magnetic material is rotatably arranged in the
housing such that it exposes the outside of the housing through the
opening and a magnet assembly arranged in a space within the
sleeve. First and second shafts are secured to the respective sides
of the magnet assembly, a third shaft secured to the sleeve at a
side which is opposed to that of the magnet assembly to which the
first shaft is connected, first and second bearing members are
arranged between the first and second shafts and the sleeve,
respectively, and a manually operable handle is secured to either
one of said second and third shafts. Means guide the housing to a
position removed from the main body and a scraper is then
detachably secured to the housing in operative association with the
sleeve. The handle is operated whereby the magnetic brush
discharges said fatigued agent through the scraper and into a
receiver.
Inventors: |
Ishimoto; Osamu (Hachioji,
JP), Tsuda; Hiroshi (Mitaka, JP),
Miyashita; Kiyoshi (Hachioji, JP) |
Assignee: |
Olympus Optical Co., Ltd.
(Tokyo, JP)
|
Family
ID: |
26346279 |
Appl.
No.: |
06/071,022 |
Filed: |
August 29, 1979 |
Current U.S.
Class: |
399/257; 101/13;
399/273; 399/276; 15/256.51; 101/DIG.37 |
Current CPC
Class: |
G03G
15/09 (20130101); G03G 15/0844 (20130101); Y10S
101/37 (20130101) |
Current International
Class: |
G03G
15/09 (20060101); G03G 15/08 (20060101); G03G
015/09 (); G03G 021/00 () |
Field of
Search: |
;118/652,203
;15/1.5R,1.5A,256.51 ;355/3DD,3DR,15 ;430/122 ;101/13,425
;427/13,25 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Kaplan; Morris
Attorney, Agent or Firm: Haseltine and Lake
Claims
What is claimed is:
1. An apparatus for discharging a used and fatigued dry developing
agent in a magnetic brush developing device for use in an
electrophotographic copying machine which developing device
comprises a housing forming a reservoir for the developing agent
and having an opening formed therein at a position which is opposed
to a charge retentive member, for retaining an electrostatic charge
image to be developed; a sleeve formed of non-magnetic material
arranged in the housing at a position whereby it is exposed to the
charge retentive member through the opening and a magnet assembly
arranged inside the sleeve; said sleeve and magnet assembly being
rotatably arranged about an axis in a given direction, comprising:
means for removably supporting the developing device along a
direction of said axis from a first developing position in the
copying machine at which the developing device develops the charge
image on the charge retentive member, to a second discharging
position out of the copying machine at which the developing device
can be accessed; means for manually rotating the sleeve and magnet
assembly together with each other, for transporting the developing
agent attracted on the sleeve surface to the opening, when the
developing device is in a second discharging position; and scraping
means detachably securable to the housing at said opening, while
the developing device is in said second discharging position, said
scraping means having an edge in contact with the sleeve surface
through the opening, so as to scrap the transported developing
agent off the sleeve enabling discharge of the developing agent
through the opening.
2. An apparatus according to claim 1, wherein said manually
rotating means comprises first and second shafts arranged coaxially
with the sleeve and connected to respective sides of the magnet
assembly, a third shaft arranged coaxially with the sleeve and
connected to the sleeve at its one side which faces to the side of
the magnet assembly to which said first shaft is secured, said
second and third shafts being rotatably journaled to the housing of
developing device, a first bearing member arranged between the
first shaft and the sleeve, a second bearing member arranged
between the second shaft and the sleeve and a manually operable
member connected to one of said second and third shafts for
rotating manually one of the magnet assembly and the sleeve, while
the other of the sleeve and the magnet assembly is made rotatable
due to a magnetic force caused between the magnet assembly and
magnetic particles in the developing agent as well as a frictional
force between the developing agent and the sleeve surface.
3. An apparatus according to claim 2, wherein: said manually
rotating means further comprises a mechanism arranged between said
second shaft and the housing of the developing device for
automatically locking the magnet assembly into a given rotational
position, when the developing device is in said first developing
position.
4. An apparatus according to claim 3, wherein said locking
mechanism comprises a ratchet secured to said second shaft and
having formed therein a recess at a given position with respect to
the magnet assembly and a claw rotatably secured to the housing of
the developing device and biased toward the ratchet in such a
manner that the claw can engage with said recess of the ratchet,
and said ratchet and claw are so constructed that ratchet can
rotate freely in one direction, but cannot rotate in the opposite
direction after the claw has been engaged with the recess of the
ratchet.
5. An apparatus according to claim 3, wherein said locking
mechanism comprises a cup-like member secured to the housing of the
developing device coaxially with said second shaft and having
formed therein a recess extending radially, a lever-like handle
journaled to said second shaft rotatably in a plane including the
second shaft and having a first position in which the handle is
inserted into the recess of cup-like member and a second position
in which the handle is pulled out of the recess, and a spring
member arranged between the handle and the second shaft for biasing
the handle to rotate into said first position.
6. An apparatus according to claim 1, wherein when the developing
device is in said second discharging position, the sleeve and the
magnet assembly are rotated in such a direction that a magnetic
brush formed on the sleeve surface rotates in a direction opposite
to that of the magnetic brush when the developing device is in said
first developing position.
7. An apparatus according to claim 1, wherein said scraping means
comprises a channel-like plate having a scraping edge and holes for
engaging with projections formed on the housing of the developing
device to secure detachably the plate to the housing.
8. An apparatus according to claim 7, further comprising receptacle
means arranged below the scraping means for receiving the
discharged developing agent through the opening.
9. An apparatus according to claim 8, wherein said receptacle means
is a box.
10. An apparatus according to claim 9, further comprising: a cover
rotatably journaled to a main body of the copying machine for
closing an opening formed in said main body through which the
developing device can be moved from the first developing position
to the second discharging position and vice versa, and a rib
provided on an inner surface of the cover, which rib serves to
position the box, when the cover is fully opened.
11. An apparatus according to claim 10, wherein said box has such a
height that the developing device pulled out of the main body can
be rest upon an upper edge of the box.
12. An apparatus according to claim 8, wherein said receptacle
means is defined by a bag formed of a soft sheet, which bag is
provided with holes corresponding to said holes formed in the
channel-like plate and a fastener of a groove type formed near an
opening of the bag.
13. An apparatus according to claim 12, wherein said channel-like
plate further comprises a bridge and projections formed on an outer
surface of the bridge, and said bag further comprises holes
corresponding to said projections.
Description
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus for discharging or
removing a developing agent from a magnetic brush developing device
for use in an electrophotographic copying or printing machine.
In the magnetic brush developing device, use is made of a two
component developing agent consisting of carriers made of magnetic
material and toners made of thermoplastic resin of low melting
point having mixed with dye or pigment such as carbon black. Such a
two component developing agent is stirred and mixed in the
developing device and the toners are charged due to friction
between the toners and carriers to a polarity opposite to that of
an electrostatic charge image on a charge retentive member such as
a photosensitive drum.
Usually the magnetic brush developing device comprises a housing
having an opening at a position which is opposed to the charge
retentive member, a sleeve made of non-magnetic material is
arranged rotatably in the housing at such a position that a part of
the sleeve surface exposes the outside of the housing through the
opening and a magnet assembly arranged fixedly in a space within
the sleeve. In such a device, when the sleeve is rotated in a given
direction, the developing agent attracted onto the sleeve surface
is transported to the opening and is brought into contact with a
surface of the charge retentive member through the opening. Also,
in such a developing device since the toners are consumed each time
the developing operation is effected, the developing device is
provided with a hopper for containing toners and a mechanism for
supplementing a given amount of toners from the hopper so as to
keep always a toner concentration of the developing agent to a
desired value. On the contrary, the magnetic carriers are not
consumed in the developing operation, but are repeatedly used.
However, the carriers are fatigued mechanically and physically due
to an agitation, secular variation, etc., and thus should be
exchanged by new carriers after the developing device has been used
for a predetermined time period or a predetermined number of
developing operation have been effected. In order to exchange the
used and fatigued carriers by new ones, the fatigued carriers must
be first discharged or removed from the developing device together
with toner particles and then a new developing agent consisting of
new carriers and toners must be introduced into the developing
device.
Heretofore, there have been proposed various kinds of apparatus for
discharging the fatigued developing agent from the magnetic brush
developing device. For instance, in Japanese Utility Model
Publication No. 50,533/76 there is disclosed a discharging
apparatus in which a box having a scraping edge is detachably
secured in a developing device in such a manner that the scraping
edge is made in contact with a rotatably arranged sleeve surface.
When the sleeve is rotated, the developing agent attracted onto the
sleeve surface is fed to the scraping edge and is scraped off the
sleeve. The developing agent thus scraped is collected in the box.
Then, the box is removed from the developing device. In such an
apparatus since a magnet assembly of the magnetic brush developing
device is fixedly arranged during the discharging operation and
thus the developing agent is fed only due to a frictional force
between the developing agent and sleeve surface, the agent is fed
or transported to the scraping edge of box only with a very small
force. Further, in this known apparatus during the discharging
operation the sleeve is rotated in a direction which is same as
that during the normal developing operation. As is well known the
magnetic brush developing device comprises a doctor blade for
limiting an amount of developing agent attracted onto the sleeve
surface. In the known discharging apparatus since the scraping edge
is arranged at a downstream side with respect to the doctor blade
(when viewing in the rotating direction of sleeve), an amount of
the developing agent fed to the scraping edge is limited by the
doctor blade. Therefore, an efficiency of the discharging operation
is very low and thus the discharging operation is a quite time
consuming one. Further, when an amount of developing agent remained
in the developing device becomes small near the end of the
discharging operation, the agent attracted onto the sleeve near the
poles of the magnet does not move together with the sleeve, but is
remained near the poles. This results in that a part of the
developing agent is always remained in the developing device
without being discharged.
Further, in the known discharging apparatus, the box for receiving
the developing agent has to be installed in a space within a
housing of the developing device and thus the developing agent is
liable to spread outside the developing device and moreover
operator's hands might be stained with the developing agent.
SUMMARY OF THE INVENTION
The present invention has for its object to provide a novel and
useful apparatus for discharging a used and fatigued developing
agent from a magnetic brush developing device, which apparatus can
avoid the above mentioned various drawbacks of the known
discharging apparatus and can effect the discharging operation in a
very efficient and easy manner.
It is another object of the invention to provide a developer
discharging apparatus in which a non-magnetic sleeve and a
permanent magnet assembly of the magnetic brush developing device
can be rotated together with each other in a direction opposite to
that for a usual developing operation.
It is still another object of the invention to provide a developing
agent discharging device in which the magnet assembly can be
automatically locked in position after the discharging operation
has been completed.
It is still another object of the invention to provide a developer
discharging apparatus in which a box of bag for collecting a
discharged developer agent can be easily set outside a housing of a
developing device.
According to the invention, an apparatus for discharging a used and
fatigued developing agent from a magnetic brush developing device
is installed in an electro-photographic copying machine, which
developing device comprises a housing having formed therein an
opening at a position which is opposed to a charge retentive member
for retaining an electrostatic charge image to be developed, a
sleeve made of non-magnetic material and arranged in the housing at
such a position that it exposes the outside of the housing through
said opening and a magnet assembly arranged inside the sleeve, one
of said sleeve and magnet assembly being arranged rotatably in a
given direction, comprises means for rotating manually the sleeve
and the magnet assembly together with each other so as to transport
the developing agent attracted on the sleeve surface to a position
at the opening under such a condition that the developing device
can be pulled out of a main body of the copying machine; scraping
means secured detachably to the housing at said opening and having
a scraping edge which is made in contact with the sleeve surface
through the opening so as to scrape the transported developing
agent off the sleeve; and receptacle means are arranged below the
scraping means for receiving the discharged developing agent
through the opening.
In a preferred embodiment of the discharging apparatus according to
the invention, said manually rotating means comprises first and
second shafts arranged coaxially with the sleeve and connected to
respective sides of the magnet assembly, a third shaft arranged
coaxially with the sleeve and connected to the sleeve at its one
side which faces to the side of the magnet assembly to which said
first shaft is secured, said second and third shafts being
rotatably journaled to the housing of developing device, a first
bearing member arranged between the first shaft and the sleeve, a
second bearing member arranged between the second shaft and the
sleeve and a manually operable member connected to one of said
second and third shafts for rotating manually one of the magnet
assembly and the sleeve, while the other of the sleeve and the
magnet assembly is made rotatable due to a magnetic force caused
between the magnet assembly and magnetic particles in the
developing agent as well as a frictional force between the
developing agent and the sleeve surface.
The preferred embodiment according to the invention is used with a
magnetic brush developing device in which the magnet assembly is
retained at a given rotational position during the normal
developing operation, the manually rotating means further comprises
a mechanism arranged between said second shaft and the housing of
the developing device for locking automatically the magnet assembly
into a given rotational position.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross-sectional view showing an embodiment of a
magnetic brush developing device to which a developing agent
discharging apparatus according to the invention is applied;
FIG. 2 is a perspective view illustrating an embodiment of a
scraping blade member according to the invention;
FIG. 3 is a perspective view depicting a lid member for covering an
opening of the developing device of FIG. 1 through which a new
developing agent can be introduced;
FIG. 4 is a cross section illustrating a magnetic brush assembly of
the developing device of FIG. 1;
FIG. 5 is a side view of the developing device of FIG. 1;
FIG. 6 is a perspective view showing an embodiment of a scraping
member according to the invention;
FIG. 7 is a perspective view showing the discharging apparatus
according to the invention;
FIG. 8 is a cross section depicting a magnetic brush assembly of
another embodiment of the discharging apparatus according to the
invention;
FIG. 9 is a side view showing the developing device of FIG. 8;
FIG. 10 is a perspective view illustrating the whole construction
of the discharge apparatus; and
FIGS. 11, 12 and 13 are perspective views showing three embodiments
of receptacle means for collecting a discharged developing agent
according to the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 is a cross section for showing an embodiment of a magnetic
brush developing device to which the present invention is applied.
In this embodiment the developing device is used for an
electrophotographic copying machine. It is apparent that a similar
device may be used for an electrophotographic printing machine. An
electrostatic charge retentive member 1 is formed as a drum which
has a surface layer made of insulating material or photoconductive
material and is rotatably journaled to a main body of the copying
machine (not shown) in a direction shown by an arrow a. By means of
a known electrophotography an electrostatic charge image may be
formed on the surface layer of the drum 1.
A developing device generally denoted by a reference numeral 2 is
removably installed in the main body of the copying machine and
comprises a magnetic brush assembly 3 including a tubular sleeve 4
made of non-magnetic material and a permanent magnet assembly 5
arranged inside the sleeve. According to the invention the magnet
assembly 5 as well as the sleeve 4 are rotatably secured to a
housing 6 of the developing device. The magnetic brush assembly 3
is arranged in the housing 6 at a position near an opening W formed
in the housing 6, so that a part of the sleeve 4 exposes the
outside of the housing through said opening W. During the
developing operation the sleeve 4 is rotated in a direction shown
by an arrow b by means of a suitable driving mechanism not shown,
but the magnet assembly 5 is fixed at a given rotational position,
i.e., a position in which at least one of the poles of the magnet
assembly 5 is placed in opposite to the charge retentive member 1.
A developing agent 7 consisting of magnetic carriers and toners is
stored in the casing 6 and is attracted onto the surface of the
sleeve 4 due to a magnetic force of the magnet assembly 5 so as to
form a so-called magnetic brush. Under such a condition when the
sleeve 4 is rotated in the direction b, the developing agent 7 is
fed along the sleeve surface and is made into contact with the
surface of charge retentive member 1. In this manner, the
electrostatic charge image on the drum 1 is developed with toners.
A doctor blade 8 for limiting an amount of agent 7 fed on the
sleeve 4, i.e., a height of furs of magnetic brush is secured by
screws 9 to a lower edge of the opening W of the housing 6. Near
the bottom of the housing 6 there is also rotatably arranged an
agitating vane 10 for stirring the agent 7 so as to electrify the
toners by friction to a given polarity.
The developing agent still remaining on the sleeve surface after
the developing operation is scraped off the sleeve 4 by means of a
scraping blade 11 shown in FIG. 2 which is swingably secured to the
housing 6 and is brought into contact with the sleeve surface due
to the gravitational force. In order to weaken the magnetically
attractive force of the developing agent with respect to the sleeve
4, no pole of the magnet assembly 5 is at a position opposite to
the scraping blade 11 as shown in FIG. 1. The developing agent
scraped off the sleeve 4 is agitated at the bottom of the housing 6
and is attracted again to the sleeve surface so as to be used
repeatedly for a new developing operation.
At an upper portion of the housing 6 there is arranged a hopper 12
for containing toners T to be supplemented to the developing agent
7. The hopper 12 is formed by a part of the housing 6 and a
resilient plate 13. An upper opening of the hopper 12 is closed by
a lid 14. At a lower opening of the hopper 12 is arranged a toner
supplying roller 15 which is rotated at a given velocity in a
direction shown by an arrow c in synchronism with the rotation of
the sleeve 4. The roller 15 has formed therein a longitudinal
recess 15a for receiving therein a given amount of toners T in the
hopper 12. During the operation a front edge of the resilient plate
13 engages with the recess 15a. In this embodiment, in order to
prevent the toners in the hopper 12 from falling down into the
bottom of the housing 6 through slit-like spaces formed between the
inner wall of casing 6 and side edges of the plate 13, the casing 6
is integrally provided with ribs 6a having a height of about 5 to
20 mm. Between the ribs and the plate 13 are arranged sheets 16
made of sponge which are cemented to the lower surfaces of ribs. In
this manner, a given amount of toners in the recess 15a of the
roller 15 can be supplied into the developing agent 7 so as to keep
a toner concentration of the agent 7 to be a desired value. In this
case, any residual toners in the recess 15a can be positively taken
out of the recess by means of the front edge of resilient plate 13.
Since the toners are fine powders, a bridge of toners might be
formed above the roller 15. In this embodiment, the resilient plate
13 vibrates each time its front edge engages with the recess 15a of
the roller 15 and thus said bridge could be broken and the toner
particles can be supplemented in a very stable and accurate
manner.
Further, at a middle of the housing 6 there is formed an opening
through which a new developing agent can be introduced into the
developing device. This opening is selectively closed by a lid 17
illustrated in FIG. 3. The lid 17 is made of plastics such as
polypropylene, polyethylene, ABS, etc., and comprises a base
portion 17a which is secured to the housing 6, a hinge portion 17b
which has a smaller thickness and a lid portion 17c which can be
rotated about the hinge portion 17b. On inner and outer surfaces of
the lid portion 17c there are formed reinforcing ribs 17d and 17e
and the inner ribs are provided with depressions 17f which
constitute a click mechanism in conjunction with projections formed
in the housing 6. These portions are formed integrally with each
other. A rotational angle of the lid portion 17c is limited to a
suitable value, preferably 60.degree. by an engagement of the outer
ribs 17e with the outer base portion 17a. Further, in case of
introducing a new developing agent the inner ribs 17d serve to
prevent the agent from overflowing from both sides of the lid
portion 17c. Moreover, since the lid portion 17c is rotated about
the hinge portion 17b having no space through which the particles
might escape the new developing agent does not leak at all through
the hinge portion. In this manner, even an unexperienced person can
easily introduce the new developing agent into the housing 6
without spilling the agent.
Next, a mechanism for holding the magnetic brush assembly 3 and a
mechanism for locking the magnet assembly 5 will be explained with
reference to FIGS. 4 and 5.
FIG. 4 is a longitudinal cross section of the magnetic brush
assembly 3. At both ends of the non-magnetic sleeve 4 are arranged
flanges 20a and 20b and a driving shaft 21 is secured to the flange
20a. The shaft 21 is journaled to the housing 6 by means of a
bearing 22. A driving gear 23 for driving the sleeve 4 by means of
a suitable driving mechanism (not shown) and a manually operating
handle 24 are fixed to the shaft 21. The handle 24 serves to rotate
manually the sleeve 4 after the developing device 2 has been pulled
out of the main body of copying machine. In this case, the gear 23
is disengaged from the driving mechanism. The magnet assembly 5 is
journaled with respect to the sleeve 4 by means of bearings 25a and
25b installed in the flanges 20a and 20b, respectively, and shafts
5a and 5b secured to respective sides of the magnet assembly 5. The
shaft 5a extends through a supporting plate 26 secured to the
housing 6 and a ratchet 27 is secured to a free end of the shaft
5a. As illustrated in FIG. 5, the ratchet 27 has formed therein a
recess 27a which engages with a claw 28 rotatably secured on the
outer surface of housing 6. The claw 28 is biased to rotate in the
clockwise direction in FIG. 5 by means of a spring 29. Therefore,
when the claw 28 engages with the recess 27a of ratchet 27 the
magnet assembly 5 does not rotate in the direction b, but the
magnet assembly 5 can rotate in the opposite direction.
Next, an operation for exchanging the old and fatigued developing
agent by a new agent will be explained.
Prior to the discharge of the old agent, a discharging plate 30
shown in FIG. 6 is prepared. The plate 30 is formed generally as a
channel and is provided with holes 31a and 31b which engage with
the heads of screws 9 for fixing the doctor blade 8 or bosses
provided on the doctor blade. As shown in FIG. 7, when the plate 30
is secured to the heads of screws 9, its scraping edge is made into
contact with the surface of the sleeve 4. It should be noted that
the plate 30 can be simply secured to the developing device 2 after
the device 2 has pulled out of the main body of copying machine in
a direction d parallel to an axis of the magnetic brush assembly 3.
Then, as illustrated in FIG. 7, a box 32 is placed under the plate
30 and the sleeve 4 is rotated in a direction opposite to the
direction b by actuating the handle 24. Hereinafter this direction
will be denoted as the direction b. Since the magnetic carriers on
the sleeve 4 and the magnet assembly 5 are attracted to each other,
when the sleeve 4 is rotated in the direction b, the magnet
assembly 5 can rotate also in the direction b, while the engagement
between the ratchet 27 and the claw 28 is released. In this manner,
the magnet assembly 5 rotates together with the sleeve 4 in the
same direction b. Therefore, the developing agent 7 to be
discharged can be strongly attracted to the sleeve surface not only
by the frictional force between the agent and the sleeve, but also
by the magnetic force of the magnet assembly 5. Thus, the
developing agent 7 can be positively fed on the sleeve surface
during the rotation of the sleeve 4 and the magnet assembly 5. The
developing agent on the sleeve surface is first brought into a
position of the scraping blade 11. As explained above, since this
blade 11 can freely rotate the developing agent which is firmly
attracted to the sleeve surface is not peeled off the sleeve
surface, but can push the scraping blade 11. Therefore, the
developing agent on the sleeve surface can pass through the
scraping blade 11 and then reach the front edge of the scraping
plate 30. Since this plate 30 is firmly secured to the housing 6,
the developing agent can be positively peeled off the sleeve
surface and is discharged into the box 32 by means of the plate
30.
As explained above, according to the invention, since the magnet
assembly 5 is rotated in the direction b together with the sleeve
4, the developing agent to be discharged can be attracted to the
sleeve surface with a very strong force and thus can be transported
positively to the scraping edge of the plate 30. Therefore, the
discharging operation can be effected in a very efficient manner
and almost all developing agent can be discharged in a very short
time.
After the old developing agent has been discharged a new developing
agent can be introduced into the developing device 2 with the lid
member 17 being opened. Then, the developing device 2 is pushed
into the main body of the copying machine after removing the
discharging plate 30 and the box 32.
In the known developing device the new developing agent is
introduced into the casing from an opening through which the
magnetic brush assembly 3 is exposed to the outside. In such a
case, the agent will be stuck to the sleeve surface and might clog
the opening and thus the introducing operation requires a skill. On
the contrary, according to the present embodiment, since the new
developing agent can be introduced through another opening provided
in the housing 6 and the lid member 17 has several functions as
explained above, the new developing agent can be simply introduced
into the housing without any particular skill.
During the discharging operation since the magnet assembly 5 is
rotated together with the sleeve 4 it is not always assured that
the magnet assembly 5 will be stopped at the given position shown
in FIG. 1. However, when the sleeve 4 is rotated in the direction b
by means of the driving mechanism and gear 23 after the developing
device has been installed into the main body the magnet assembly 5
is also rotated in the direction b due to the magnetic force
produced between the magnetic carriers and the magnet assembly 5.
Thus, the claw 28 will engage with the ratchet 27 within one turn
of the magnet assembly 5. In this manner, the magnet assembly 5 can
be automatically locked at the given rotational position.
FIGS. 8, 9 and 10 show another embodiment of the developing agent
discharging apparatus according to the invention. In this
embodiment, same parts as those of the previous embodiment are
denoted by the same reference numerals. The mechanism for
supporting rotatably a magnetic brush assembly 3 including a sleeve
4 made of non-magnetic material and a permanent magnet assembly 5
is same as that of the previous embodiment. During the developing
operation the sleeve 4 is rotated by means of a gear 23 and a shaft
21 which is connected to the sleeve, while the magnet assembly 5 is
made stationary by means of a locking mechanism which will be
explained hereinafter. Whereas during the discharging operation for
a fatigued developing agent the magnet assembly 5 is manually
rotated and the sleeve is also rotated due to a magnetic force
produced between the magnet and the magnetic carriers and a
frictional force caused between the sleeve surface and
carriers.
As illustrated in FIG. 8, a shaft 5a is connected to one side of
the magnet assembly 5 and extends outwardly beyond a holding plate
26 integrally with which is formed a substantially cup-like member
34. When the developing device is pulled out of a main body of the
copying machine in a direction d, an operator can grasp the
cup-like member 34. A handle holding member 35 is secured to a free
end of the shaft 5a which supports a lever-like handle 36 having a
pin 37 secured at its free end. As best shown in FIG. 9, the handle
36 is rotatably secured to the holding member 35 by means of a
shaft 38 and a coiled spring 39 is arranged between the handle 36
and the holding member 35 so as to bias the handle to rotate in the
anti-clockwise direction in FIG. 8. In order to lock the magnet
assembly 5 at a given position the cup-like member 34 has formed
therein a recess 34a in which the handle 36 can be installed. The
handle 36 has such a length that it can engage with side walls of
the cup-like member 34 defining the recess 34a. Therefore, the
shaft 5a and thus the magnet assembly 5 does not rotate relative to
the housing 6 when the handle 36 is installed in the recess
34a.
FIG. 10 shows the developing device 2 pulled out of the main body
of the copying machine. When the developing device is to be
withdrawn from the main body, a cover 40 is first opened. Then, the
developing device 2 is pulled in the direction d along guide
members 41 and 42 on which edges 43 and 44 formed at a bottom of
the housing 6 can slide. After the developing device 2 has been
withdrawn to a given extent as shown in FIG. 10, a scraping plate
30 is secured to the housing 6 by means of an engagement of holes
31a and 31b with heads of screws 9 for fixing a doctor blade to the
housing 6 as explained hereinbefore. A box 32 for collecting the
developing agent has been placed on an inner wall of the cover 40
before the developing device 2 is withdrawn from the main body. To
this end, the cover 40 is formed in such a manner that it can be
held horizontally. Further, on the inner wall of the cover is
formed a rib 45 for positioning the box 32. In this embodiment, the
box 32 also serves as a supporting member for the withdrawn
developing device 2.
Then, the handle 36 is pulled out of the recess 34a of the cup-like
member 34 and is rotated manually in a direction b with the aid of
the pin 37 which is then extending outwardly. The rotational
direction b of the handle 36 may be marked on the handle 36. In
this manner, the magnet assembly 5 can be rotated in the direction
b and then the sleeve 4 is also rotated in the direction b by a
frictional force caused between the sleeve surface and magnetic
carriers which are attracted onto sleeve surface due to the
magnetic force caused by the magnet assembly. Then, the carriers
and toners are transported on the sleeve surface also in the
direction b and are scraped off the sleeve by the edge of scraping
plate 30. The developing agent thus scraped is collected in the box
32. After the discharging operation has been finished the handle 36
may be stopped at an arbitrary angular position. Then the handle is
turned about the shaft 38 and is urged against the outer surface of
the cup-like member 34 by means of a resilient force of the coiled
spring 39. After a new developing agent has been inserted into the
housing 6 through an opening of the housing 6, while the lid 17
being opened, the developing device 2 is pushed into the main body
of copying machine along the guide members 41 and 42. When the
developing device is installed into a given position, a gear 23
shown in FIG. 8 is engaged with a driving mechanism. When the
developing operation is started, a shaft 21 and thus the sleeve 4
are rotated in the direction b and the magnet assembly 5 is also
rotated in the same direction b. Therefore, the handle 36 is
automatically fitted into the recess 34a within a first rotation of
the magnet assembly 5. In this manner, the magnet assembly 5 can be
locked at the given position with respect to the housing 6.
The present invention is not limited to the embodiments explained
above, but many modifications can be conceived within the scope of
the invention.
In the above embodiments, the developing agent collecting box 30 is
used as the member for supporting the developing device 2 which has
been pulled out of the main body of copying machine. But, it is not
necessary to do so. For instance, the withdrawn developing device 2
may be supported exclusively by the guide members 41 and 42 or by a
supporting member provided on the inner wall of the cover 40. In
such a case, it is not necessary to use the rigid box 32.
FIGS. 11, 12 and 13 illustrate three embodiments of a bag for
collecting the discharged developing agent. In an embodiment shown
in FIG. 11, a scraping plate 30 having a pair of holes 31a and 31b
formed therein is secured to the housing 6 of the developing device
2 together with a bag 46 which may be formed by a soft sheet of
synthetic material such as a vinyl sheet. The bag 46 has formed
therein a pair of holes corresponding to the holes 31a and 31b.
When the scraping plate 30 and bag 46 are secured to the housing 6,
the plate 30 is inserted into the bag 46 in such a manner that the
holes in the bag 46 are aligned with the holes 31a and 31b in the
scraping plate 30. After the discharged developing agent has been
collected in the bag 46, the bag 46 is removed from the housing 6
together with the scraping plate 30 and then the plate is removed
from the bag 46. Then, an opening of the bag is closed along a
fastener 47 of a groove type by simply pressing upper and lower
sheets of the bag 46 against each other.
FIG. 12 illustrates a modification of the assembly of a scraping
member and a bag. In this embodiment, a scraping plate 48 comprises
a bridge portion 48a so as to form a substantially tubular body and
has formed therein a pair of holes 49a and 49b in the plate 48 for
engaging with the screws 9 of the developing device 2 and a pair of
projections 50a and 50b on the bridge portion 48a for engaging with
corresponding holes formed in a bag 51 shown by a dot and chain
line. In this manner, the bag 51 can be firmly secured to the
scraping member. The bag 51 has formed therein near its opening a
fastener 52 of a groove type.
FIG. 13 shows still another embodiment in which a scraping member
53 and a bag 54 are formed integrally with each other. The scraping
member 53 is provided with a pair of holes 55a and 55b for securing
it to the housing 6 of the developing device. The bag 54 is formed
therein a fastener 56 of a groove type. In this embodiment, after
the developing agent is introduced into the bag 54, the whole
assembly 53 and 54 may be discharged. Therefore, the operation is
much simpler than the previous embodiments.
Further, in the above explained embodiments, the sleeve 4 or the
magnet assembly 5 is made rotatable due to the magnetic force
caused between the magnetic carriers and the magnet. However, it is
also possible to provide a one-way clutch between the sleeve and
the magnet assembly. Then, the sleeve and magnet assembly can be
simultaneously rotated in a positive manner during the operation
for discharging the developing agent.
In the above embodiments, use is made of the two component
developing agent consisting of the magnetic carriers and toner
particles, but use may be made of a single component developing
agent.
As explained above, according to the invention, since the
non-magnetic sleeve and the magnet assembly are simultaneously
rotated during the operation for discharging the developing agent,
the developing agent can be positively and effectively transported
on the sleeve to the scraping position and thus almost all
developing agent can be discharged within a relatively short time.
Further, since there is provided the locking means for positioning
the magnet assembly at a given position the magnet assembly can be
automatically set in position after the discharging operation.
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